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Analog Devices Inc./Maxim Integrated MAX1623EAP+
- Part No.:
- MAX1623EAP+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX1623EAP+.pdf
- Description:
- IC REG BUCK ADJ 3A 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:632
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Product details
Overview
MAX1623EAP+ from Maxim Integrated is a 3A, synchronous step-down DC-DC regulator with integrated 55mΩ PMOS and 60mΩ NMOS power switches, designed for local CPU I/O and bus-termination supplies in notebook/desktop computers. It delivers ±1% output accuracy (including line/load regulation), 94% typical efficiency at 3A, and supports fixed 3.3V/2.5V or adjustable 1.1V–3.8V outputs from a 4.5V–5.5V input.
For engineers reviewing the MAX1623EAP+ datasheet, MAX1623EAP+ pinout, MAX1623EAP+ application, or MAX1623EAP+ equivalent, key selection criteria include constant-off-time PWM control up to 350kHz, Idle Mode™ operation for light-load efficiency, thermal shutdown at +145°C, and 20-pin SSOP package compatibility with space-constrained computing power rails.
Technical Context
The MAX1623EAP+ employs current-mode PWM control with programmable off-time via external RTOFF, enabling precise trade-offs between switching frequency (50–350kHz), inductor size, and output noise. Its internal 1.10V reference (±1.5% over –40°C to +85°C) feeds both the feedback loop and external system use.
Operation includes seamless transition between PWM mode (>1.25A load) and Idle Mode™ (pulse-skipping below 1.25A), with dynamic current limiting (3.65A min, 4.65A max) and synchronous rectification eliminating Schottky losses. The transconductance amplifier at COMP pin sets loop stability via external 470pF–2000pF capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 3A continuous load capability - supports CPU I/O and bus-termination rails without external current boosting. |
| Input Voltage Range | 4.5V to 5.5V - matches standard 5V system rails with ±10% tolerance for robust desktop/notebook operation. |
| Output Accuracy | ±1% including line and load regulation - ensures stable core logic voltage under dynamic CPU load transients. |
| Switching Frequency | Up to 350kHz - enables compact 4.7µH inductors and reduces EMI compared to lower-frequency buck converters. |
| Efficiency | 94% typical at 3A - minimizes thermal load in thermally constrained laptop daughter cards and embedded systems. |
| Shutdown Current | <1µA - preserves battery life during system sleep states in portable computing applications. |
| Thermal Shutdown | +145°C threshold with 20°C hysteresis - protects against sustained overload or poor PCB heatsinking without latch-up. |
Pinout & Package
MAX1623EAP+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with exposed thermal pad (not electrically connected), optimized for high-current density and thermal dissipation on compact PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 3, 5, 16, 18, 20 | LX | Switching node connecting internal PMOS drain and NMOS drain - carries full AC inductor current; requires low-inductance layout to minimize EMI. |
| 2, 4, 6 | IN | Main 4.5V–5.5V power input - internally tied to PMOS source; must be decoupled with 4.7µF + 10µF ceramic capacitors within 5mm. |
| 7 | SHDN | Active-low shutdown control - pulled high to VCC for normal operation; <1µA shutdown current enables deep-sleep power management. |
| 8 | FBSEL | Feedback select input - configures output: unconnected = 3.33V, VCC = 2.525V, GND/REF = adjustable mode (1.1V–3.8V). |
| 9 | TOFF | Off-time programming input - sets tOFF = RTOFF/110kΩ (µs); adjusts switching frequency and optimizes inductor/noise trade-offs. |
| 10 | FB | Feedback input - senses output directly (fixed mode) or via resistor divider (adjustable mode); regulates when VFB = VREF (1.10V). |
| 11 | GND | Analog ground reference - separate from PGND to isolate sensitive feedback and reference circuitry from high di/dt noise. |
| 12 | REF | 1.10V precision reference output - ±1.5% over temperature; bypassed with ≥0.1µF ceramic; usable as system-level voltage reference. |
| 13 | COMP | Integrator capacitor connection - sets loop compensation with 470pF–2000pF to ground; determines transient response and stability. |
| 14 | VCC | Analog supply input - powers internal analog blocks; must be bypassed with 10Ω + 4.7µF RC filter to suppress switching noise. |
| 15, 17, 19 | PGND | Power ground - internal NMOS source connection; ties high-current return paths; must be joined to IN and C2 grounds at single point. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated 60mΩ NMOS switch replaces lossy Schottky diode - improves heavy-load efficiency by 3–5% and eliminates reverse recovery noise. |
| Idle Mode™ operation | Automatic pulse-skipping below 1.25A load - reduces gate charge and switching losses to maintain >85% efficiency at 10mA loads. |
| Constant-off-time PWM | Programmable tOFF (0.5–4µs) via TOFF pin - enables stable operation across wide input/output ratios without slope compensation. |
| Pin-selectable output | Three configurations: 3.33V (FBSEL open), 2.525V (FBSEL = VCC), or adjustable (FBSEL = GND/REF) - eliminates external resistors for common CPU I/O voltages. |
| Thermal protection | Non-latching +145°C junction shutdown with 20°C hysteresis - prevents permanent damage during short-circuit or airflow-loss conditions. |
| Internal 1.10V reference | ±1.5% accuracy over –40°C to +85°C - provides stable reference for both regulation and external analog circuits without added components. |
Applications
| 5V to 3.3V Conversion | Notebook Computer CPU I/O Supply |
|---|---|
Use Scenario: Converting main 5V system rail to stable 3.3V for PCI/PCIe I/O buffers and chipset interfaces. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated 3.3V at up to 3A with fast transient response. Use Value: ±1% output accuracy maintains signal integrity across wide temperature and load ranges; 94% efficiency reduces thermal load on densely packed motherboard layers. |
Use Scenario: Powering CPU address/data I/O banks in ultra-thin notebooks where board space and thermal headroom are severely limited. IC Role / Device Role / Timing Role: Local point-of-load regulator with integrated switches - eliminates external MOSFETs and simplifies layout. Use Value: 20-pin SSOP footprint and Idle Mode™ extend battery runtime during low-activity states while supporting burst-mode CPU workloads. |
| Desktop Computer Bus-Termination Supply | CPU Daughter Card Supply |
Use Scenario: Providing clean, low-noise 3.3V termination voltage for high-speed parallel buses (e.g., legacy ISA, LPC) in industrial desktop systems. IC Role / Device Role / Timing Role: Dedicated bus-termination regulator with tight load regulation to prevent signal reflection and timing skew. Use Value: 1% load regulation error ensures consistent termination impedance across 0–3A load range; synchronous rectification minimizes voltage droop during bus arbitration spikes. |
Use Scenario: Powering modular CPU daughter cards in server blades or embedded controllers requiring field-replaceable compute modules. IC Role / Device Role / Timing Role: Compact, self-contained buck solution with pin-strapped 2.5V or 3.3V output - eliminates manual configuration. Use Value: Fixed-output modes reduce BOM count and assembly risk; thermal shutdown protects card-level power integrity during hot-swap events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS5430DDAR | 3A, 5.5–36V input, external MOSFETs, 500kHz max frequency - lacks integrated synchronous rectifier and fixed 3.3V/2.5V options. | Used in higher-input industrial systems; requires external gate drivers and loop compensation. | Select when input exceeds 5.5V or when design requires >36V input range - not drop-in compatible with MAX1623EAP+. |
| RT8205AZSP | 3A, 4.5–24V input, integrated synchronous switches, ±2% output accuracy, 600kHz max - no Idle Mode™ or pin-selectable fixed outputs. | Targets general-purpose embedded power; less optimized for CPU I/O transient response and low-noise computing rails. | Choose for cost-sensitive non-computing applications where ±2% accuracy and absence of light-load optimization are acceptable. |
Compared with TPS5430DDAR and RT8205AZSP, the MAX1623EAP+ uniquely combines pin-selectable 3.3V/2.5V outputs, Idle Mode™ for sub-10mA efficiency, and ±1% accuracy in a 20-pin SSOP - making it purpose-built for space-constrained, thermally sensitive computing power rails where simplicity and precision are critical.
Availability
MAX1623EAP+ is available at Aetrix Electronics and suitable for notebook computer CPU I/O supply, desktop bus-termination supply, and CPU daughter card supply requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to +85°C.
Supply support for MAX1623EAP+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for computing, industrial, and communications markets.
The MAX1623EAP+ belongs to Maxim's high-efficiency, integrated-power-switch buck regulator product line, engineered specifically for low-voltage, high-current point-of-load conversion in space- and thermal-constrained computing platforms.
FAQ
What output voltage options does the MAX1623EAP+ support?
The MAX1623EAP+ supports three output configurations via the FBSEL pin: 3.33V (FBSEL left unconnected), 2.525V (FBSEL tied to VCC), or adjustable 1.1V–3.8V (FBSEL grounded or connected to REF). Each mode uses the same internal 1.10V reference, ensuring ±1% accuracy across all settings. The MAX1623EAP+ does not require external resistors for fixed outputs, reducing BOM count and layout complexity in computing power designs.
How does Idle Mode™ improve light-load efficiency in the MAX1623EAP+?
Idle Mode™ in the MAX1623EAP+ activates automatically when load current falls below 1.25A, switching from constant-off-time PWM to pulse-skipping operation. This reduces gate-drive and switching losses, maintaining >85% efficiency even at 10mA loads. The MAX1623EAP+ transitions seamlessly between modes without output voltage disturbance, making it ideal for CPU I/O rails that experience rapid load transients between active and idle states.
What is the role of the TOFF pin on the MAX1623EAP+ and how is it configured?
The TOFF pin on the MAX1623EAP+ sets the switch off-time using an external resistor (RTOFF) from TOFF to GND, where tOFF = RTOFF/110kΩ (µs). This allows designers to optimize switching frequency (50–350kHz), inductor size, and EMI profile. For example, a 110kΩ resistor yields ~1µs off-time and ~300kHz operation with 5V→3.3V conversion. The MAX1623EAP+'s constant-off-time architecture ensures stable regulation without slope compensation across input/output variations.
Does the MAX1623EAP+ include thermal protection, and how does it behave under overload?
Yes, the MAX1623EAP+ incorporates non-latching thermal shutdown that triggers at +145°C junction temperature and resumes operation after cooling by 20°C. During sustained overload (e.g., output short), the MAX1623EAP+ cycles on/off to limit average power dissipation and prevent permanent damage. This behavior protects both the IC and downstream circuitry while maintaining system-level fault resilience - critical for unattended desktop and embedded deployments.
Can the REF pin of the MAX1623EAP+ be used as a system-level precision reference?
Yes, the REF pin of the MAX1623EAP+ provides a buffered 1.10V reference accurate to ±1.5% over –40°C to +85°C, rated for up to 10µA external load. For optimal noise and accuracy, it should be bypassed with ≥0.1µF ceramic (0.47µF recommended for low-jitter applications). Loading REF above 5µA slightly reduces MAX1623EAP+ output voltage due to reference load-regulation error, so shared reference use requires careful current budgeting.
MAX1623EAP+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.1V (2.525V, 3.33V)
- Voltage - Output (Max):
- 3.8V
- Current - Output:
- 3A
- Frequency - Switching:
- Up to 350kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
MAX1623EAP+ FAQ
1.How can I place an order for MAX1623EAP+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1623EAP+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX1623EAP+ reliable?
The price and inventory of MAX1623EAP+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1623EAP+ is usually 5 days.
3.What payment methods are accepted for MAX1623EAP+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1623EAP+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1623EAP+?
MAX1623EAP+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1623EAP+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX1623EAP+?
For technical support, including MAX1623EAP+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1623EAP+ requirements.
6.How does Aetrix verify that MAX1623EAP+ is sourced from the original manufacturer or authorized distributors?
All MAX1623EAP+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX1623EAP+ meets industry standards.
7.What is the process for return or replacement of MAX1623EAP+?
All MAX1623EAP+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1623EAP+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX1623EAP+ part is unused and in its original packaging.
Return procedure for MAX1623EAP+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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